Engine piston



May 27, 1930. c. B. DREvlTsoN ENGINE PISTON Filed May 28, 1929 May 27, 1930. c. BfDREvlTsoN ENGINE PIS'TON Filed May 28, 1929 y Patented May 2l?, 1930 UNITED s'rafresl P.a'lvlsN'r OFFICE CARL B. DBEVITSON, OF SOMERVILLE, MASSACHUSETTS ENGINE Applieationiled May 28,

I outer end, and a cylindrical skirt whose open end constitutes the inner end of the piston.

One object of the invention is to provide the inner end of the piston with means cooperating with the bore of the cylinder during anA inward stroke of the piston to accumulate under pressure oil present on the lbore of the cylinder and force it between the bore and the periphery of the piston, to prevent objectionable metal contact of the piston with the cylinder, and the noise which often results from such contact, and to ensure suicient lubrication.

Another object is to provide the piston with additional means cooperating with the bore of`the cylinder, whereby a hydraulic cushion of oil is maintained between the piston and bore, to prevent the vobjectionable noise known as side slap. l

Of the accompanying drawings forming a part of this specicatiom- Figure 1 is a side elevation of a piston embodying the invention. l

Figure 2 is a section on line 2-2 of F1g' ure l, and a sectional View of a portion of the cylinder.

Figure 3 is a section on line 3-3 of Fig- `ure 1.

Figures 4, 5, 6, 7 and 8 are views similar to Figure 1, showing difiere'. t embodiments of the invention.

Figure 9 is a section on line 9,-9 of Figure 4.

Figure 10 Figure 7.

Figure 11 is a section on line ll-ll'of Figure 7.

The same reference characters lndicate the same parts in all of the figures.

The piston shown by the drawings includes a head 12, constituting the closed outer end, and a skirt 13, whose inner end constitutes the open inner end of the piston. .The usual grooves 14 adjacent the head, recelve expansible piston rings 15, contacting with the bore of the cylinder 16. The skirt 1s provlded is a section online 10-101of PISTON 1929'. serial No. 366,611.

with the usual bearings 17 for the connecting- I rod wrist-pin. 18 designates a beveled face intersecting the periphery and the inner end of the piston, and preferablyv constituting a frusto-conical zone at an obtuse angle with the cylindrical periphery of the piston. Said periphery usually has a loose fit in the piston bore, so that the periphery and the cylinder bore are lubricated by oil supplied for that purpose.

The width of the face v18 is preferably about one quarter of an inch when the diameter of the piston is about three and onehalf inches. The taper or bevel of said face `is preferably as indicated by Figure 2, the

lower edge of the face 18 being separated from the cylinder bore by a space of substantial width tapering to the periphery of the piston.

The arrangement is such that the face 18 cooperates with the cylinder bore in forming a tapered oil-receiving throat 19, in which oil is accumulated under pressure during an inward stroke of the piston, and forced outward to form a iilm filling the crevice between the piston and the cylinder bore. Said film effectively lubricates the surfaces forming the crevice and prevents the objectionable and noisy contact of the piston with the cylinder often observed, particularly after the opposed surfaces have become worn.

To provide a hydraulic cushion of oil be# tween the periphery of the piston and the bore of the cylinder, and thereby eliminate 20, spaced from the beveled face 18, and a groove 21, extending from said face to the recess 20. The bottom of the recess is oHset The recess 20, and the groove 2l, are adapted-to cooperate with the cylinder bore in forming an oil pocket and a duct connecting the pocket with the throat 19, the bore forming the outer side of said pocket and duct. The arrangement is such that during an inward stroke of the piston, oil accumulated under pressure in the throat 19, is forced side slap, I form in said periphery a recess .85

. posite ends of each recess to the face 18. The

grooves open into the upper portion of the recess, so that oil is trapped below the discharge ends of the grooves.

' Figures 4 and 9 show additional recesses above the recesses 20, and grooves 21 extending from the recesses 20 to the recesses 20a.

The recess 20'sl1own by Figures 5 and 6 has an outlet 23 at one end communicating with V an outer recess 2Gb.

Figure 6 shows only one groove 21, communicating with the recess 20. l

Figure Z shows a recess 20C, independent of the recess 20, and grooves 21c extending between the recess 20c and the face 18. n

The recesses are preferably oblong, their major axes being substantially at right angles With the longitudinal center of the piston, so that the oil pockets are elongated horizontally, or in a direction at right angles with the axis of the piston. The recesses are also preferably located between the bearings 17, and the inner end of the piston, although, as shown by Figure 8, there may be a supplemental recess 2Od between the bearings and the outer end of the piston, and an elongated groove 21d extending between said recess and the face 18. In this. instance, there are two recesses 20, between which the groove 21d extends.

' The inclination of the face 18 relative to the periphery` of the piston should be, as above stated, substantially as shownvby the drawings. I have found that when the face 18y 1s so inclined that it is at approximately ten degrees with the periphery of the piston i in any longitudinal section thereof, as here shown, the angle 18' formed by the intersection of said face with the periphery ofthe cylinder, is suiiiciently obtuse to prevent an inward wiping of the oil accumulated lby the inward movement of the piston, and create such pressure on the accumulated oil as to force the oil outward into the crevice between the piston and cylinder and into the groove yIf the inclination of the face 18 were at apnot cause such pressure on the accumulated loil as to adequately force the same outwardly into said crevice and grooves.

The width ofthe faces 18 should be such that the distance between the receiving mouth of the pocket 19 and the angle 18a is considerably greater than the width of said mouth, so as shown by Figures 2 and 10. The linclined face 18 may extend entirely around the piston and form acontinuous zone. Said face may, however, be interrupted by yshoulders 25 on the periphery of the piston, as shown by Figure 6, said shoulders constituting stops at opposite ends of a segmental inclined face portion 18a, preferably of greater length than the pocket`20. The oil wiped from the cylinder by the'face yportion 18, is prevented bythe stops 25 from iowing 'i parallel with the inner end of the piston, and is caused to flow only through the groove 21 into a pocket or pockets communicating with said groove, so that an adequate supply of oil enters said pocket or pockets.l

It will be understood that when the face is interrupted as shown by Figure 6,' there will be a similar 'interrupted face portionv at th opposite side of the piston. v

I claim: i

1. The combination with an engine cylinder, of a piston having a beveled face intel'- secting the periphery of the inner end of the piston, a recess in said periphery spaced from said face, and a groove in said periphery extending from the beveled face to the recess, said face, recess, and groove being adapted to cooperate with the bbore of the cylinder in forming a tapered oil-containing throat having a receiving mouth, an oil pocket, and a duct connecting the throat with the pocket, the arrangement being such that, during an inward stroke of the piston, oil on the cylinder bore is. accumulated under pressure in the throat, forced through the duct, and trapped in the pocket to constitute a Khydraulic cushion, whereby side slap is eliminated.

2. The vcombination with an engine cylinder, of a piston having a beveled face interr secting the periphery of the inner end of the piston, a recess in said periphery spaced from l said face, and a groove `in said periphery extending from the beveled face to the recess, said face, recess, `and groove being adapted to cooperate with the bore of the cylinder in forming a tapered oil-containing throat havy ing a receiving mouth, an oili pocket, and a duct connecting the throat with the pocket, the arrangement being such that, during an inward stroke of the piston, oil on the'cylinder bore is accumulated under pressure in the throat, forced through the duct,and trapped in the pocket to constitute a hydraulic cushion, 4whereby side sla-p is eliminated, and perfeet lubrication is maintained, the recess being oblong and its major axis substantially said face, and a groove in said periphery exl at right angles with the longitudinal axis of the piston.

3. The combination of an engine cylinder, of a piston having a beveled face vintersecting the periphery of the inner end of the piston, a recess in said periphery spaced from said face, and a groove in said periphery extending from the beveled face to the recess, said face, recess, and groove being adapted to cooperate with the bore of the cylinder in forming a tapered oil-containing throat having a receiving mouth, an oil pocket, and a duct connecting the throat with the pocket. the arrangement being such that, during an inward stroke of the piston, oil on the cylinder bore is accumulated under pressure in the throat, forced through the duct, and trapped in the pocket to constitute a hydraulic cushion, whereby side slap isleliminated, the beveled face being inclined at approximately ten degrees with the periphery of the piston, the

width of said face being such that the depth l of said throat is greater than the width of the receiving mouth thereof.

4. The combination of an engine cylinder,

of a piston having a beveled face intersectv ing the peripherynf the inner end of the piston, a recess in said periphery spaced from tendingfrom the beveled face to the recess, said face, recess, and groove being adapted to cooperate with the bore of the c linder in forming a tapered oil-containing t roa-t having a receiving mouth, an oil pocket, and a duct connecting the throat with the pocket, the arrangement being such that, during an inward stroke of the piston, oil on the cylin der bore is accumulated under pressure in the throat, forced through the duct, and trapped in the pocket to constitute a hydraulic cushion, whereby side slap is eliminated, said beveled face being interrupted by stops formed by portions of the periphery of the piston,

. whereby oil wiped from the cylinder by the piston is caused to flow through said groove into said recess.

In testimony whereof I have aixed my signature.

CARL B.y BREVI-Tseu.- 

